Presence Of Corrosion Inhibitor Research Articles

Novel Environmentally Friendly Nanomaterials for Drag Reduction of the Emulsified Acid System.

Matrix acidizing is a technique that is widely used in the petroleum industry to remove scales and create channels in the rock. Removal of scales and creation of channels (wormhole) enhance productivity. Conventional acidizing fluids, such as hydrochloric acid (HCl) for carbonate and a mixture of hydrofluoric acid (HF) and HCl acid, are used for the matrix acidizing process. However, these fluids have some drawbacks, including strong acid strength, corrosion at high temperatures, and quick reactions with scale and particles. Emulsified acid systems (EASs) are used to address these drawbacks. EASs can create deeper and narrower wormholes by reducing the reaction rate of the acid due to the external oil phase. However, EASs have a much higher viscosity compared to conventional acidizing fluids. The high viscosity of EASs leads to a high drag that restricts pumping rates and consumes energy. This study aims to utilize environmentally friendly and widely available nanomaterials as drag-reducing agents (DRAs) of the EAS. The nanomaterials used in this study are carbon nanodots (CNDs). CNDs have unique properties and are used in diverse applications in different industries. The size of these CNDs is usually smaller than 10 nm. CNDs are characterized by their biocompatibility and chemical stability. This study investigates the use of CNDs as DRAs for EAS. Several experiments have been conducted to investigate the CNDs as a DRA for the EAS. The developed EAS was initially tested for conductivity and drop-test analysis to ensure the formation of an inverted emulsion. Thereafter, the thermal stability for the range of temperatures and the rheological properties of the EAS were evaluated to meet the criteria of field operation. Then flow experiments with EASs were conducted before and after adding the CNDs to investigate the efficacy of drag reduction of EASs. The results revealed that CNDs can be used as viscosity reducers for the EAS, where adding the CNDs to the EAS reduces the viscosity at two different HCl concentrations (15 and 20%). It reduces the viscosity of the EAS in the presence of corrosion inhibitors as well as other additives to the EAS, showing its compatibility with the field formulation. The drag reduction was observed at the range of temperatures investigated in the study. The conductivity, stability, and rheology experiments for the sample taken after the flow experiment are consistent, ensuring CNDs work as a DRA. The developed EAS with CNDs is robust in terms of field mixing procedures and thermally stable. The CNDs can be used as a DRA with EAS, which will reduce drag in pipes, increasing pumping rates and saving energy.

Computational Prediction of Electrochemical Corrosion Rates of Copper in the Presence of Corrosion Inhibitors

Computational prediction of corrosion rates is still a challenging issue in the field of metal corrosion. In this study, we proposed a computational model to predict the corrosion rates of copper in the presence of adsorption-type corrosion inhibitors using density functional theory calculations, microkinetic simulation, and machine learning. The model-calculated corrosion current and potential of clean copper are close to values obtained in available experiments. The copper corrosion rates in the presence of inhibitors were further predicted using the adsorption free energy of adsorbed inhibitors and the inhibitor concentration in solution to describe the effects of inhibitors. The proposed model was applied to predict corrosion inhibition efficiency by combining it with a machine learning model. The combining model exhibited that it was more interpretative and accurate than a machine-learning-only model in predicting corrosion inhibition efficiencies of organic compounds on copper.

Duplex Coating Combing Vanadate-Intercalated Layered Double Hydroxide and Ce-Doped Sol-Gel Layers on Aluminum Alloy for Active Corrosion Protection.

In this study, a duplex coating system (LDH-V/SG-Ce) of vanadate-intercalated layered double hydroxide (LDH) and Ce-doped sol-gel (SG) layers was developed for the purpose of active corrosion protection of the aluminum alloy AA2024. ZnAl-LDH film was grown in situ on the surface of an aluminum alloy using a hydrothermal method and intercalated with V2O74- anions as corrosion inhibitors, and sealed with a Ce (III)-doped silane coating using a sol-gel technique. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses were used to analyze the microstructure, surface functional groups and structure of the LDH-V/SG-Ce film. The uniform and compact silane layer was covered both in the pores and on top of the LDH film. The results of glow discharge optical emission spectroscopy (GDOES) indicated that V2O74- and Ce (III) ions were loaded in the LDH layer and silane film, respectively. The potentiodynamic polarization results showed that the corrosion current density of the bilayer system in the presence of corrosion inhibitors was reduced to 1.92 × 10-8 A/cm2. Electrochemical impedance spectroscopy (EIS) results showed that the LDH-V/SG-Ce duplex coating could provide effective protection for the aluminum alloy after being exposed to a corrosive solution for 14 days.

Molecular Dynamics Simulation of Methane Hydrate Formation on Pipeline Surface in the Presence of Corrosion Inhibitors

Molecular Dynamics Simulation of Methane Hydrate Formation on Pipeline Surface in the Presence of Corrosion Inhibitors

A novel corrosion inhibitive system comprising Zn-Al LDH and hybrid sol-gel silane nanocomposite coating for AA2024-T3

A novel layered double hydroxide (LDH)/silane bilayer system was introduced as an effective non-hazardous protective coating for AA2024-T3. Also, the loaded corrosion inhibitors' effect on the bilayer coating system's active anticorrosion properties was studied. For this purpose, diethyldithiocarbamate (DEDTC) molecules, as an eco-friendly corrosion inhibitor, were intercalated in the LDH conversion layer. Furthermore, Ce3+ cations were loaded in the sodium montmorillonite and then incorporated in the mixture of tetraethoxysilane and γ-amino propyltriethoxysilane. The grazing incidence X-ray diffraction, Fourier-transform infrared spectroscope, and scanning electron microscope (SEM) equipped with energy dispersive spectroscope were used to analyze the structural, surface functional groups, microstructure, and chemical composition of the coatings. Electrochemical impedance spectroscopy, potentiodynamic polarization, and electrochemical current noise technique were employed to investigate the layers' protection behavior. Based on the obtained results, the presence of corrosion inhibitors in the structure of the coatings resulted in a dramatic enhancement in the protection behavior of the substrate. The polarization results illustrated that the corrosion current density of the bilayer system was reduced from 170 to 6.7 nA/cm2 after employing the corrosion inhibitors into the coating structure. The electrochemical tests and SEM results illustrated the induction of the active anticorrosion properties for the bilayer system containing the DEDTC molecules and Ce3+ cations. The total noise energy for the scratched double-layer coating in the presence and absence of corrosion inhibitors was calculated to be 4.1 and 9.5 pA2, respectively, indicating efficient corrosion inhibition.

Fatigue crack growth rate parametric study on subsea X65 pipeline steel girth welds in H2S/CO2 environments

Steel catenary risers, subsea flowlines and pipelines that are used to transport oil and gas products are susceptible to corrosion fatigue in environments containing CO2 or H2S, termed sweet and sour respectively. Fatigue crack growth rates (FCGRs) in such environments are generally enhanced compared to that in air due to crack tip dissolution or the embrittling effect of ingressed hydrogen generated from the corrosion process. Several factors influence the FCGR including partial pressure of CO2 or H2S, pH value, microstructure, temperature and loading frequency. Although there are reports in the literature on the effect of each of the parameters on FCGRs, data on the combined effects, for example, frequency and temperature are not well documented. The work conducted in this study focussed on the effects of temperature and loading frequency on FCGR of X65 pipeline steel welds in sweet and mildly sour environments. The results demonstrate the importance of the selection of the appropriate test temperature and loading frequency in FCGR laboratory tests in order to avoid use of non-conservative or unduly conservative results in engineering critical assessment (ECA). Furthermore, the influence of low concentrations of H2S and the presence of corrosion inhibitor on FCGRs of carbon steels was investigated. The dominant corrosion processes under specific testing conditions are proposed.

Machine learning modeling of time-dependent corrosion rates of carbon steel in presence of corrosion inhibitors

We have employed supervised machine learning methods to model measurements of corrosion rates of carbon steel as a function of time when corrosion inhibitors are added in different dosage and dose-schedules. The experiments show that the time-profile of corrosion rates depend on the dose schedule, while the final rates depend mainly on the environment severity. We find that Random Forest was the best algorithm that predicted the entire time-profile of corrosion rates with the mean squared error ranging from 0.005 to 0.093. Sensitivity of corrosion rates to changes in the environmental variables are well-predicted by the trained Random Forest model.

Effects of pre-filmed FeCO3 on flow-induced corrosion and erosion-corrosion in the absence and presence of corrosion inhibitor at 60 °C

In CO2 environments, an increase in the temperature can influence carbon steel flow-induced corrosion (FIC) and erosion-corrosion (EC) degradation processes. Increasing temperature typically results in the acceleration of electrochemical degradation mechanisms in the absence of protective corrosion product layers. Furthermore, the presence of sand in corrosive process fluids could aggravate the service conditions. Although protective iron carbonate (FeCO3) film or/and corrosion inhibitors are capable of suppressing corrosion in CO2-containing environments typical of oil and gas production, their ability to suppress degradation and their associated mechanisms in erosion-corrosion environments is less understood. This work focuses on understanding the ability of FeCO3 to protect the steel surface in the absence and presence of corrosion inhibitor and their interactions in flow-induced and erosion-corrosion systems at 60 °C. The effect of the temperature increase is investigated based on results obtained in a previous study performed at 25 °C. FeCO3 filmed carbon steel specimens were developed using an autoclave at 60 °C, pH 6.6 and 30 bar in a 1.5 wt% NaCl CO2-saturated solution over 48 h. The FeCO3 covered specimens were evaluated in FIC and EC environments at 60 °C and a flow velocity of 15 m/s in the presence and absence of 1000 mg/L sand and 100 ppm of a commercially available corrosion inhibitor. Results indicate that the sole presence of an FeCO3 layer is not sufficient to retard the corrosive process of carbon steel at 60 °C under EC conditions. However, the commercial corrosion inhibitor was observed to worked synergistically with the FeCO3 layer to reduce the corrosion degradation component in both the presence and absence of sand particles. The erosion component is also reduced in erosion-corrosion environments as a result of the combined presence of FeCO3 and corrosion inhibitor.

A study of corrosion processes in a demineralized aqueous medium in the presence of bacterial cells

Our earlier results indicate the feasibility of considering the microbiological contamination of closed and reversible cooling and water supply systems, given the effect of the microbial cells on the corrosion processes taking place there. The results show a possibility of transition metal ions acting as regulators and modifiers of microorganisms’ growth processes under conditions of an osmotic stress and starvation.The aim of the present work is to study the effect of transition d-metal ions (Zn2+ and Cr3+), both separately and in the presence of known antiskalants, oxyethylenediphosphonic acid (OEDFh) and nitrilotrimethylphosphonic acid (NTMFh), on the effectiveness of the corrosion protection and the course of the biological corrosion in a demineralized environment.Microorganisms belonging to different systematic affiliations were selected for the study of the biocorrosion processes: Bacillus sp. and Pseudomonas sp. These microorganisms belonged to different physiological groups of bacteria and had opposite types of life strategies. They differred significantly in their ability to survive under the influence of various factors. They could exist in closed systems of water consumption (with sharp temperature changes, oxygen starvation, a presence of toxic substances used for water conditioning). Bacillius and Pseudomonas strains were cultured on commonly used agar media, after which a cell suspension was prepared. For all bacterial strains used, the seeding dose was 108 cells‧cm-3. It was determined using turbidometric control methods and bacterial density standards. The effect of the microorganisms on the corrosion processes was followed in stationary bioreactors of a volume of 125 cm3. A solution of 0.1 % NaCl was added as a model medium to which corrosion inhibitors (Zn2+, Cr3+, OEDPh and NTMPh) were added at a concentration of 5 mg‧dm-3. At each stage of preparation, the suspension was thoroughly mixed, after which the metal samples were introduced to the reactor in the form of electrodes so that the entire surface of the electrode was completely immersed in the water. The metal samples were made of St 20 carbon steel. Each study of model water with metal plates was of 3 weeks duration. The intensity of the corrosion process was evaluated once a week. The rate of the biological corrosion was determined by the gravimetric method. The inhibition factor (j) and the degree of the corrosion protection (Z, %) of the samples in presence of corrosion inhibitors and bacteria were calculated. The negative value of this indicator indicated a change of the direction of the process, i.e. an activation of the corrosion process.The obtained data show that the presence of microorganisms significantly modifies the anti-corrosion effect of the heavy metal ions. The range offluctuations of the degree of the corrosion protection in presence of bacteria of the genus Pseudomonas is greater than that of the genus Bacillus. The dynamics of the protective effect in presence of both strains is characterized by significant changes (a decrease and a subsequent gradual increase of the degree of the corrosion protection). The highest intensity of the corrosion process is observed during the first week of the interaction in a model environment containing bacterial cells and anticorrosive agents. Then, the direction of the process changed and there was shown a slight protective effect at the 5-15 up to 36 % level. It is also demonstrated that the anti-corrosion compositions containing NTMPh provide a greater increase of the corrosion process rate in presence of microorganisms.The study of the presence of microorganisms on the corrosion proceeding demonstrates their ability to provide a significant effect. The bacteria can activate the corrosion process, which complicates the inhibitors behavior.

Influence of inhibitors on the corrosion behavior of the X5CrNi18 10 stainless steel‐welded joint

AbstractThis study considers the corrosion behavior of the X5CrNi18 10 stainless steel‐welded joint in NaCl solution, with and without the presence of several corrosion inhibitors (NaNO3, Ce(NO3)3, and CeCl3). The degree of sensitization of the welded joint to intergranular corrosion is determined using the electrochemical potentiokinetic reactivation method with a double‐loop method. Pitting corrosion tests are performed by the potentiodynamic method. Resistance to general corrosion and the stability of the passive film is assessed based on the results of electrochemical impedance spectroscopy measurements, as well as on the values of the corrosion and passivation current. The main goal of this study is to determine the relation of the welded joint microstructure to general and pitting corrosion in the presence of the corrosion inhibitors. The value of pitting potential for the base metal and weld metal in the presence of the NaNO3 or Ce(NO3)3 inhibitor is shifted to potentials in the transpassive area. The pitting potential for the heat‐affected zone also possesses a noticeable higher value. However, nitrate ions do not increase the general corrosion resistance of any part of the welded joint. CeCl3 does not increase resistance to general or pitting corrosion.

An amino‐based protic ionic liquid as a corrosion inhibitor of mild steel in aqueous chloride solutions

AbstractProtic ionic liquids (PILs) have shown to be promising substances as corrosion inhibitors (CIs). In line with this, the aim of this study is to study the performance and propose the corrosion inhibition mechanism of N‐methyl‐2‐hydroxyethylamine (M‐2HEAOL) and bis‐2‐hidroxyethylamine (B‐HEAOL) oleate, for mild steel, in a neutral chloride solution. Electrochemical characterization was conducted under static and hydrodynamic conditions, and it was revealed that M‐2HEAOL and B‐HEAOL worked as mixed‐type CIs with more interference on the anodic reaction. Inhibition efficiency depended on the concentration reaching 97% of inhibition efficiency in 5 mmol/L concentration. Scanning electron microscopy, optical interferometry, Raman spectroscopy, and Fourier‐transform infrared spectroscopy are used to elicit the chemical composition of the surface film and corrosion morphology of steel in the presence of CIs, the adsorption processes of which involved physical and chemical adsorption between metal and different parts of ionic liquids. The results allowed the proposition of a corrosion inhibition mechanism.

Uticaj kupri jona na koroziono ponašanje mesinga CuZn-42 u prisustvu inhibitora korozije u kiseloj sredini

In this work we are presented our results of investigations of corrosion behavior of CuZn-42 brass in acid sulphate solution, in presence of corrosion inhibitors and cupric ions. Based on the recorded anodic polarisation curves, it was concluded that with increased concentrations of cupric ions, the values of corrosion current densities also increase. The effect of corrosion inhibitors on the corrosion behaviour of brass is analyzed in the work and it is concluded that the concentration of inhibitors is 10-2% shows inhibition effect.

Corrosion Behaviour of Mg Alloys in Alkaline Solutions and in Alkali-Activated Binders

The reprocessing of spent fuels from UNGG (Uranium Natural Graphite Gas) nuclear reactors in France generates cladding wastes mainly composed of Mg alloys. The management of these wastes involves their immobilization in hydraulic binders with high pH interstitial solutions (12.5<pH<13.7). In the case of magnesium corrosion, the choice of these materials for immobilization and storage is not straightforward due to the characteristic reactivity of these alloys, which is caused by several aspects [1]. First, magnesium corrosion is strongly influenced by the pH and the composition of the electrolyte (the pore solution of hydraulic binder). Furthermore, the electrochemical potential of Mg places this metal as an anode with respect to several materials [2] (e.g. residual graphite materials initially present in the fuel assemblies or steel from the container), which can create galvanic couplings and accelerate corrosion. Previous work has found low corrosion rates of Mg-Zr alloys and low H2 releases produced when Mg is immobilized in a Na-geopolymer mortar in the presence of fluorides (magnesium corrosion inhibitor) [3]. Similarly, there was a low release of H2 from corrosion during the galvanic coupling between Mg-Mn and graphite, as well as the formation of thinner corrosion product layers when Mg-Mn is immobilized in an alkali-activated slag mortar [4]. These results have contributed to the choice of these two materials as the most appropriates for embedding these wastes. Nevertheless, the electrochemical mechanisms responsible for this weaker corrosion, compared to conventional cementitious matrices, must be identified in these two reference scenari. The purpose of this work is to investigate the corrosion processes that occur once the Mg alloys are embedded in their immobilization matrices. The goal is to understand the phenomena that lead to low corrosion rates in these materials, in the case of general and galvanic corrosions. From these guidelines, a study of the cementitious matrices (porosity, resistivity and gas diffusion) and its interstitial solutions (pH, ionic species and conductivity) was carried out in order to identify the main parameters that can limit the corrosion rate of magnesium. The corrosion behavior of Mg alloys against these conditions has been tested in model solutions and in each cementitious binders using electrochemical techniques (OCP, ZRA, EIS and polarization curves), gravimetry and surface characterization (XRD, SEM/EDS and FIB/STEM). Both matrices are relevant for the storage of Mg wastes and have a thermodynamically favorable pH for magnesium passivation due to the precipitation of Brucite (Mg(OH)2) on its surface. The high resistivity of the alkali-activated slag and the possible consumption of O2 by the sulphides of the pore solution are favorable aspects to reduce galvanic corrosion rate. In the case of the Na-geopolymer/NaF, the oxygen concentration can also limit the rates of galvanic corrosion, since, during storage, oxygen access could be restrained. However, the presence of corrosion inhibitors (silicates and fluorides) is mainly responsible for the reduction of Mg corrosion, because of a protective film formed at the MgZr/Na-geopolymer interface. This corrosion rate may vary with the concentration of fluoride available in solution and is probably related to the nature of the corrosion product formed on the magnesium surface. General and galvanic corrosion in the Na-geopolymer/NaF mortar were quantified by gravimetric measurements and in both cases the nature of the corrosion products was characterized by scanning electron microscopy (SEM/EDS), X-ray diffraction (XRD) and FIB/STEM (Focused Ion Beam/Scanning Transmission Electron Microscope). The results revealed the stratification of the corrosion products found at the Mg-Zr/Na-geopolymer interface and were in good agreement with the experiments performed in the model alkaline solution. Magnesium corrosion in the Na-geopolymer/NaF mortar is rather limited by the chemistry of the interstitial solution. [1] K. W. Guo , “A Review of Magnesium/Magnesium Alloys Corrosion and its Protection”, Recent Patents on Corrosion Science, vol. 2, pp. 13-21, 2010. [2] G. L. Song and A. Atrens, “Corrosion Mechanisms of Magnesium Alloys”, Adv. Eng. Mater., vol. 1, no. 1, pp. 11–33, 1999. [3] D. Chartier, B. Muzeau, L. Stefan, J. Sanchez-Canet and C. Monguillon, “Magnesium alloys and graphite wastes encapsulated in cementitious materials: Reduction of galvanic corrosion using alkali hydroxide activated blast furnace slag”, Journal of Hazardous Materials, vol. 326, pp. 197-210, 2017. [4] D. Lambertin, F. Frizon and F. Bart, “Mg-Zr alloy behaviour in basic solutions and immobilization in Portland cement and Na-geopolymer with sodium fluoride inhibitor”, Surface and Coating Technology, vol. 206, pp. 4567-4573, 2012.

Effect of cation type of chloride salts on corrosion behaviour of steel in concrete powder electrolyte solution in the presence of corrosion inhibitors

Abstract In this research, effect of cation type of chloride salts on corrosion behaviour of steel was determined by potentiodynamic polarization test in concrete powder electrolyte solution in presence of corrosion inhibitors. Results showed that cation type of chloride salts not only affected compressive strength of concrete but also passivity of steel and chloride binding. The decreasing trend of bound chloride concentration was CB: CaCl2 > CB: MgCl2 > CB: NaCl. Formation of various compounds in concrete was confirmed through XRD and FTIR spectroscopy analyses. Sodium nitrite was more effective in enhancing passivity of steel than di-Sodium hydrogen phosphate.

Understanding the Scales Formation Inhibition Mechanism on C-Steel in a Sour media

Corrosion control in sour environments is a serious challenge for oil and gas industry. One of the approaches to mitigate such problem is to use corrosion inhibitors (CI). The selection of a single or a mixture of CIs for a particular oil or gas production, transportation or storage facility depends on different parameters e.g. the ratio between carbon dioxide and hydrogen sulfide, pH, pressure, temperature, and brine chemistry where different kinds of iron sulfide and/or iron carbonate layers can be formed. To select the right corrosion inhibitor/s, it is highly crucial to understand the mechanism of corrosion of C-steel and its inhibition in H2S systems in absence and presence of CIs [1,2]. In this work, the electrochemical behavior of C-steel in (i) deionized water (DIW) and (ii) different NaCl solutions were examined in an H2S system. A series of experiments were conducted at different temperatures and two concentrations of inhibitors (A and B). The corrosion behavior of C-steel was investigated by measuring the open circuit potential (OCP), linear polarization resistance (LPR), and potentiodynamic polarization (PDP) in addition to scanning electron microscopy (SEM) coupled with an energy dispersive X-ray (EDX) besides Raman spectroscopy (RS). The results have shown that the corrosion rate of C-steel gradually decreased then stabilized with time in the inhibited solutions. The inhibition efficiency was found to increase in the presence of both types of inhibitors with temperatures. Surface analysis shows that no film of corrosion products existed. In fact, CIs controlled the corrosion process and prevented passive film formation (iron sulfide), even in the presence of H2S in all tests. 2.5.0.0 2.5.0.0

Adsorption and performance of ammonium-based ionic liquids as corrosion inhibitors of steel

Methyltrioctylammonium methyl sulfate (TMA) and trimethyltetradecylammonium methyl sulfate (TTA) were synthetized as novel quaternary-ammonium-derived ionic liquids (ILs) in order to be evaluated as corrosion inhibitors (CIs) of API-X52 steel in 1 M HCl. Electrochemical techniques were used to evaluate the anticorrosive effect, finding that TMA and TTA worked as mixed-type CIs and inhibited the corrosion process depending on the temperature, immersion time and IL concentration, being remarkably effective at 40 °C, which was attributed to the high thermal stability of the methyl sulfate anions. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to elicit the chemical composition and surface morphology of steel in the presence of CIs whose adsorption processes involved strong electrostatic interactions between the metal, chloride ions, methyl sulfate anions and quaternary ammonium cations in the ILs. The results allowed the development of a corrosion inhibition mechanism.

Effect of operating parameters and corrosion inhibitors on foaming behavior of aqueous methyldiethanolamine solutions

Corrosion inhibitors are one of the main causes of amine foaming in gas sweetening units. A detailed understanding of amine foaming behavior in the presence of corrosion inhibitors is of great importance if the foaming is to be minimized. In this work, a comparative study was carried out to investigate the foaming tendency and bubbles characteristics of aqueous methyldiethanolamine (MDEA) in the presence of fatty acid-based (Bis(2-Hydroxyehyl)cocoalkylamine; BHCL) and hydrocarbon-based (HCB) corrosion inhibitors. The effect of different operating parameters such as nitrogen flow rate, corrosion inhibitor concentration, foaming time, solution temperature and pore size of the gas diffuser were studied using foam scan instrument. The results showed that on increasing the foaming time, solution temperature and corrosion inhibitor concentrations, the foaming tendency increased. For BHCL, the foam height tends to decrease with a high flow rate and a small pore size of the gas diffuser. Nevertheless, the opposite trend was observed in the presence of the HCB corrosion inhibitor. Depending upon the type of corrosion inhibitors, careful optimization of the operating conditions showed a high potential to minimize amine foaming.

Study on tea leaves extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

Corrosion inhibitor from extraction of plant has been considered as the most preferable and most chosen technique to prevent corrosion of metal in acidic medium because of the environmental friendly factor. In this study, black tea leaves extraction was tested as corrosion inhibitor for mild steel in 0.1M of hydrochloric acid (HCl) with the absence and presence of corrosion inhibitor. The efficiency and effectiveness of black tea as corrosion inhibitor was tested by using corrosion weight loss measurement experiment was carried out with varies parameters which with different concentration of black tea extract solution. The extraction of black tea solution was done by using aqueous solvent method. The FT-IR result shows that black tea extract containing compounds such as catechin, caffeine and tannins that act as anti-corrosive reagents and responsible to enhance the effectiveness of black tea extract as corrosion inhibitor by forming the hydrophobic thin film through absorption process. As a result of weight loss measurement, it shows that loss in weight of mild steel reduces as the concentration of inhibitor increases. The surface analysis was done on the mild steel samples by using SEM.

Expired Fluoxymesterone Drug as Sustainable Corrosion Inhibitor for Mild Steel (MS) in 3 M HCL Solution: Experimental Investigations towards Mitigation of Metal Dissolution

The current research presents corrosion inhibition activity of expired Fluoxymesterone drug on the mild steel (MS) in the 3 M HCl solution. The atomic absorption spectroscopy, Tafel polarization and AC impedance spectroscopy studies have been done to verify the corrosion protection efficiency. The surface studies were carried out by scanning electron microscopy (SEM) technique. Atomic absorption spectroscopy results show that, the amount of iron content is low in the presence of corrosion inhibitor when compared with bare system. Tafel plots clearly hint the mixed corrosion inhibition property (inhibition of both anodic and cathodic corrosion process) of expired Fluoxymesterone drug over the MS surface in the acidic environment. From the AC impedance spectroscopy technique, it is observed that, the charge transfer resistance values enhances with a rise in the concentration of the corrosion inhibitor. Surface studies by SEM also support the atomic absorption spectroscopy, potentiodynamic polarization (Tafel plot) and AC impedance spectroscopy results.

Radial Basis Function Neural Network for Electrochemical Impedance Prediction at Presence of Corrosion Inhibitor

Simulation and preparing predictive model of electrochemical impedance Nyquist plots based on radial basis function neural network (RBFNN) are presented in this paper. The RBFNN as a powerful predictive system predicts the real and imaginary parts of impedance as a function of time, temperature and inhibitor concentration. The mean R value of 0.9996 as regression coefficient and mean square error (MSE) value of 1.72 × 10 −3 as results show the validity of proposed method for simulation and prediction of electrochemical impedance spectroscopy (EIS) in different environmental situations.